ESA's Historic Rosetta Mission Extended Through September 2016

By Emily Carney, on June 24th, 2015

Rosetta and Philae at comet 67P. Credit: ESA–C. Carreau/ATG medialab

The European Space Agency (ESA) announced that the Rosetta mission, which saw the spacecraft successfully orbit a comet and set a lander down upon its surface in a series of historic firsts, has been extended. Just days after it was revealed Philae, Rosetta’s lander, was “alive” again after being silent for seven months, ESA stated it will continue Rosetta’s mission through September 2016, when the agency will attempt setting the orbiter upon Comet 67P/Churyumov-Gerasimenko’s surface. Rosetta’s original science mission was set to end in December of this year, but on Tuesday, June 23, ESA’s Science Programme Committee announced the extension.

The comet will make its closest approach (perihelion) to the Sun on Aug. 13, so Rosetta’s extended mission will tell scientists more about the comet’s behavior afterwards. In addition, the continued science mission will shed more light upon changes occurring upon the comet’s surface due to the close solar approach, and ESA also related it is hoped that Rosetta’s observations will contribute to Earth-based observations. Moreover, ESA revealed that Rosetta will also keep attempting to positively identify Philae, which is nestled in a landing site called “Abydos,” surrounded by craggy, rocky formations.

From ESA: “This single frame Rosetta navigation camera image of Comet 67P/Churyumov-Gerasimenko was taken on 7 June 2015 from a distance of 203 km from the comet centre. The image has a resolution of 17.3 m/pixel and measures 17.8 km across.” Image Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

ESA also added, “During the extended mission, the team will use the experience gained in operating Rosetta in the challenging cometary environment to carry out some new and potentially slightly riskier investigations, including flights across the night-side of the comet to observe the plasma, dust, and gas interactions in this region, and to collect dust samples ejected close to the nucleus.” This wouldn’t be the first time an ESA cometary explorer has braved some very risky conditions; in 1986, the Giotto spacecraft (which has been referred to as “Rosetta’s grandfather”) flew in close proximity to Halley’s comet. While that space probe was damaged, it survived, and returned images that remain incredible even at present time.

By fall of next year, with Rosetta’s propellant mostly depleted and not enough solar energy for normal operations, the spacecraft’s mission will be at its end. Patrick Martin, Rosetta’s mission manager, discussed the current plans to set Rosetta down on Comet 67P’s surface:

“This time, as we’re riding along next to the comet, the most logical way to end the mission is to set Rosetta down on the surface. But there is still a lot to do to confirm that this end-of-mission scenario is possible. We’ll first have to see what the status of the spacecraft is after perihelion and how well it is performing close to the comet, and later we will have to try and determine where on the surface we can have a touchdown.” ESA stated that this kind of scenario may take place over a period of three months.

From a scientific perspective, it will be very interesting to see data returned concerning the comet’s close approach to the Sun, how it behaves afterwards, and what Rosetta finds as it approaches closer and closer to the comet before its “death spiral.” Matt Taylor, Rosetta’s project scientist, sounded enthusiastic: “This is fantastic news for science. We’ll be able to monitor the decline in the comet’s activity as we move away from the Sun again, and we’ll have the opportunity to fly closer to the comet to continue collecting more unique data. By comparing detailed ‘before and after’ data, we’ll have a much better understanding of how comets evolve during their lifetimes.”

This news comes shortly after it was announced that Philae, Rosetta’s lander, again made contact with its orbiter and Earth seven months after its apparent demise on Comet 67P’s surface. On June 13, it was revealed that signals were received at European Space Operations Centre in Darmstadt at 22:28 CEST. A previously published AmericaSpace story related: “It was also revealed by ESA that Philae ‘spoke’ to ground controllers for 85 seconds, its first communication since November 2014, and data reveals that the lander has been awake for some time. Dr. [Stephan] Ulamec [DLR’s Philae project manager] continued, ‘We have also received historical data – so far, however, the lander had not been able to contact us earlier.’”

Since then, Rosetta and Philae have continued to stay in contact, showing that Philae’s first “phone call” wasn’t a fluke. On June 19, another signal was received in Darmstadt at 15:37 CEST (confirmed by the Lander Control Centre at the German Space Centre, DLR), followed by another signal at 15:54 CEST. According to ESA: “The downlink was stable; the two contacts received by Rosetta lasted two minutes each. Both delivered numerous packets of lander housekeeping and status data, 185 in total, which are still being analysed at the time of this writing.” At present time, no science data has been received from Philae. Controllers are continuing to optimize Rosetta’s orbit for better communication with its lander; it is hoped that time slots for communication can be better predicted, so Philae can commence science operations once again.

Rosetta and Philae have brought the Earth a series of unparallelled firsts; with the nine-month extension of the mission, it is anticipated that, as the saying goes, “The best is yet to come.”

From the European Space Agency (ESA), 2014: “Using the CIVA camera on Rosetta’s Philae lander, the spacecraft snapped a ‘selfie’ at comet 67P/Churyumov–Gerasimenko.” Image Credit: ESA/Rosetta/Philae/CIVA

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